The focus of this project is to investigate resident corneal cell interaction with the immunoregulatory cytokine IL-10. Studies will be carried out with cultured human and murine corneal epithelial cells and fibroblasts. RT- PCR analysis will be used to determine precisely which resident corneal cells express IL-10 receptor mRNA. Flow cytometry and immunohistology will be used to search for the protein product on the different corneal cell types. The consequences of IL-10 binding to its receptor on corneal cells will be analyzed from the perspective of determining whether ligand binding leads to suppressed cytokine/chemokine mRNA and/or protein synthesis. Prior RT-PCR and ELISA studies in our laboratory have shown that IL-10 suppresses IL-6 mRNA and protein synthesis. The applicant hypothesizes that IL-10 inhibits cytokine synthesis at the level of gene transcription or interferes with mRNA stability. Preliminary data indicate that human and mouse corneas possess mRNA for IL-10. The applicant will test whether resident corneal cells make IL-10 protein. Positive results would suggest that IL-10 may function as an autoregulatory factor for resident corneal cells. The basic information generated by these studies may prove useful for devising new approaches to control ocular inflammation.